abstract = "We introduce Memory with Memory Genetic Programming
(MwM-GP), where we use soft assignments and soft return
operations. Instead of having the new value completely
overwrite the old value of registers or memory, soft
assignments combine such values. Similarly, in soft
return operations the value of a function node is a
blend between the result of a calculation and
previously returned results. In extensive empirical
tests, MwM-GP almost always does as well as traditional
GP, while significantly outperforming it in several
cases. MwM-GP also tends to be far more consistent than
traditional GP. The data suggest that MwM-GP works by
successively refining an approximate solution to the
target problem and that it is much less likely to have
truly ineffective code. MwM-GP can continue to improve
over time, but it is less likely to get the sort of
exact solution that one might find with traditional
GP.",